Automatic brake



March 13, 1928. 1,662,635 P. BURKE ET Al. AUTOMATIC' BRAKE Filed sept.15. 292e I z shuts-sheet 2 P "i mi A TTORNEYS.

Patented Mar. I3, 1928.

UNITED STATES y 1,662,635 PATENT OFFICE.

'.PAUI.- BURKE AND .ARTHUR4 ORLOFF, OF GREEN BAY, WISCONSIN, ASSIGNORSTO NORTHWEST ENGINEERING CORPORATION, F GREEN BAY, WISCONSIN, A COR-PORATION or WISCONSIN.

AUTOMATIC BRAKE.

Application tiled September 15,A 1926. Serial No. 135,627.

The invention relates to automatic brakes,-

and more particularly to brakes ot this type used in connection withhoisting apparatus. -Where an automatic brake is associated with ahoisting drum when the drum is turned to wind in the hoist-ing` cablethe brake. is automatically released butwhen the drum rotates in theopposite direction the brake is automatically applied and to permit otthe paying out ot the hoisting cable under the influence of the loadmeans under the control ofy the operator are provided to release theautomatic brake, and the object of the present invention is to improvebrake mechanism of this character by providing a single spring forinitiating the tension in the brake member which spring tension .is

relieved by the operator to permit ot thecontrolled release ot thebrakeand further to provide for a. complete release of the brake byrelieving the live end ot the band ot the spring tension.

The invention further consists in the sev eral features hereinafterdescribed and more particularly defined by claims at the conclusionhereof.

In the drawings Fig. l vis a Side elevation View of brake mechanismembodying the invention; l

.Fig 2 is an end elevationview thereof;

Fig. `3) is a detail view of parts of the brake mechanism. A

Fig 4 is a detail lsectional view taken on the line 4-4 of Fig. 2.

In the drawings the numeral 4 designates a power shaft having a hoistdrum 5 thereon upon which the hoist line 6 is mounted, and 7 the brakedrum associated with the hoist drum.l

A brake member 8 in the form of a band is connected at its dead end byan eyebolt 9 to an oscillatoryT member 10, here shown in the iorm ot abell-crank lever pivotally mounted on a shaft 11 secured to a bracket 12associated with a ixed frame member 13. .The live end 14 of the bra-kemember 8 is connected by a link 15 .to one arm of a bellcrank lever 16which' is pivotally connected by pin 17- to one arm of the member 10.The distance of the pin 16 from the shaft 11 is greater than thedistance ot the pin 1S at the dead end of the band from the sha'lt 11.The member 10 is also provided with a stop projection 19 engageable withthe end ot the frame 13 to limit the swinging movef ment in onedirection, and a stop projection 20 is al-so providedon the lever 1Gengagcablc with thc member 10 to ett'ect a. complete automatic releaseof the drum, as hereinafter described.

For putting tension upon the band a singlo spring 21 is interposedbetween the trame 13 and one arm 22 of a bell-crank lever 23 which ispivotcd on a pin 24 associated with the bracket 12 and has its other arm25 provided with a pin 26 connected by a link 27 and a pin 28 to the arm29 of the lever 16. A bias to the brake mechanism in the direction ofengagement is elfected by ottsetting the center of articulation deinedby pin 26 to the lett of the fixed pivot point 1l of the lever 10 sothat the spring 21 imposes a continuous slight tendency on mem- ,her'lOto rotate it in a brake-applying direction which, as here shown, isanti-clockwise.

As a means, under the control of the operator, for releasing the brakewe have shown a foot-pedal 3() pivoted at 31 and connected by a link 32with the arm :22 otl the lever 23.

lVith this construction when the drum 5 is rotated anti-clockwise thetension in end 9 is less than that in end 14 and under these conditionsthe lever 10 will swing upwardly, thus releasing the band and allowingfree rotation of the drum in a direction to Wind in the cable 6.

When the drum G is rotated in a clockwise direction, the pedal beingfree` the tension in end 9 exceeds that in end 14 and the lever` 10swings down or in an anti- .clockwise direction until stop 19 comes intocontact with t-he frame 13, the pull of the end 14 of the band beingthen resisted by the pressure of spring Q1 acting through lever 23, linkQT and lever 16. For ordinary loads, that are within the capacity ofspring 21, this movement of the lever 10 will cause the brake to beapplied tightly to the drunr and hence automatically stop rotation in adirection in which the cable is paid out.

With the brake applied and holding a load, tending to rotate the drum ina clockwise direction, if pressure be applied to the toot-pedal inamount sutlicient to cause compression ot sprino 21. then lever 16.acted upon by the spring through link 27 and lever Q3, will cause theend 14 of the band to move toward the drum, thus releasing the brake andallowing the drum to rotate in a, clockwise direction and hence permitthe los cable 6 to pay out and allow the load to descend.

When under conditions of anti-clockwise rotation the lever 10 swingsupwardly or in a clockwise rotation to release the brake and due to thereaction of spring 21 upon the lever 23, link .2T and lever 16, the end20 of said lever 16 abuts against the lever 10 and moves with it so asto ell'ect a complete automatic release ot' the brake from the drum.

lt`urthermore, the oti'setting of the center of pin 26 relative to thecenter of oscillation of lever 1() and to the left thereotl enables thespring 21 to impose a continuous tendency to rotate the lever 10 in adownward or anti-clockwise direction tending to apply the brake thusgiving a bias to the brake mechanism in the direction ot' engagement.

From the foregoing description it will be noted that when throughclockwise rotation of the drum the lever 10 swings upwardly the brakewill be automatically applied and that independent movement of the lever16 will then release the brake, and that when the drum rotates in theopposite direction the brake is automatically released by the movementof both of the levers 1() and 16, the abutting engagement between saidlevers under these conditions causing a complete automatic release.

We desire it to be understood that this invention is not to be limitedto any particular form or arrangement of parts except in so far as suchlimitations are specilied in the claims.

What we claim as our invention is:

1. In an automatic brake, the combination with a brake drum and a brakeband therefor, of a pair of members movable relative to each other andhaving the brake band associated therewith whereby the band isautomatically applied by the movement of one of-said members andindependently released by the movement of the other member, and meansfor moving both members together to ell'ect a complete automatic releaseof said brake band.

2. In an automatic brake, the combination with a brake drum and a. brakeband therefor, of a pair of members movable relative to each other andhaving the brake bandassociated therewith whereby the band isautomatically applied by the movement of one of said members andindependently released by the movement ot' the other member, and meansfor tensioning the hand including connections to one member oll'setrelative to those of the other member to bias the brake mechanism in thedirection ot engagement.

3. ln an automatic brake, the combination with a brake drum and brakeband therefor, of a pair ot' members movable relative to each other andhaving the brake band associated therewith whereby the band isautomatically applied by the movement ot one of said members andindependently released by the movement ot the other member, of means forellecting the movement ot said last-named member to release the bralte,and a spring associated with said means and acting therethrough uponsaid members to etl'ect the normal tensioning ol' the brake band.

4. In an automatic brake, the combination with a brake drum and bralv'eband therefor, of a pair of pivoted levers pivotally connected togetherand separately connected to the ends of the band whereby the band isautomatically applied by the movement ot' one ot said levers andindependently released by the movement ot' the other lever7 saidlast-.named lever having abutting engagement with said lirst-nan1edlever to cause both levers to move together' to ell'ect a conn pleteautomatic release of said band from said drum when rotating in adirection opposite to that producing engagement.

5. In an automatic brake, the combination with a brake drum and a brakeband therefor, of a pair of pivoted levers pivotally connected togetherand separately connected to the ends of the band whereby the band isantomatically applied by the movement. oll one of said levers andindependently released by the movement oit the other lever, a springassociated with said last-named lever for tensioning the brake, andmannally-operated Ameans for relieving said tension ol' `said spring andindependently moving raid lastnamed lever,

In testimony whereof, we allix our signatures.

PAUL BURKE. ARTHUR ORLOFF.

